This invention relates to a plate-type filter press embodying centrally suspended filter plates with guide means to prevent the plates from swinging back and forth and a flushing device having a spray tube which is insertable from below and between adjacent filter plates.
In filter presses heretofore employed, in particular for the dewatering of sewage sludges, the filtration chambers are opened by pulling adjacent filter plates apart so that the filter cake can drop out. A disadvantage encountered in the use of known apparatus lies in that remnants of filter cake adhere to the filter cloths and that these remnants gradually decrease the permeability of the filter cloths. Accordingly, the cloths are flushed at regular intervals with water under pressure to remove such remaining solids.
This flushing operation is carried out by moving a spray tube into the space between every two adjacent, separate filter plates. The simplest solution, in view of kinematics, is a design wherein the spray tube is horizontally arranged and guided at both ends so as to be introduced from below into the open filter chambers between adjacent filter plates.
Heretofore, this washing operation has been a time consuming procedure. This is primarily due to the guide elements which prevent the filter plates from swinging back and forth while they are being moved. Such prior art guide elements are in the form of rods which extend adjacent the lower edges of the filter plates over the entire length of the filter press and are engaged from above by conventional lug means arranged on the filter plates. This design requires the rods to be unlocked and disengaged from the lugs before the spray nozzle can be operated.